Dynamic pseudo-continuous arterial spin labeling angiography using a 3D-radial multi-spoke spoiled gradient-recalled...

Accurate identification of arterial feeders and draining veins is critical for treatment decision-making in patients with intracranial high-flow vascular lesions. Currently available MRI sequences lack the temporal and spatial resolution needed for this task. A novel time-resolved pseudo-continuous arterial spin labeling (ASL) angiography sequence with high spatial and temporal resolution was developed, and image quality metrics relevant to clinical performance were assessed.

Ten volunteers and eight patients with intracranial high-flow vascular lesions underwent a brain MRI protocol, augmented with the new sequence with multi-spoke (1-3) readouts and dynamic, sliding-window reconstruction. For each of the acquisitions, image quality was assessed using a 5-point Likert scale, as well as SNR and SNR efficiency. Spatial and temporal resolution and acquisition time were compared with standard-of-care sequences used to assess high-flow vascular lesions.

The time-resolved angiographic sequence achieved high isotropic spatial resolution (0.68 mm³), comparable to time of flight (TOF) MRA, but higher than that of contrast-enhanced (CE)-MRA, and a higher temporal resolution (200 ms) than CE-MRA. Multi-spoke acquisitions demonstrated a significant increase in SNR and SNR efficiency compared to single-spoke acquisitions while maintaining an overall high image quality rating and at a 31% reduced scan time relative to the single-spoke variant.

This study demonstrated the clinical feasibility of a novel time-resolved ASL sequence using a multi-spoke 3D-radial readout with a vessel-signal optimized flip angle sweep. Sufficient SNR, superior spatial and temporal resolution to CE-MRA, and a comparable spatial resolution to TOF MRA were achieved in a clinically reasonable acquisition time.